A State Department bureau spent $630,000 buying "Likes" for its Facebook page, according to the agency's inspector general. The money bought the Bureau of International Information Programs roughly two million thumbs-up on its English-language page, and around 450,000 on its foreign-language pages between March 2011 and March 2013.

Despite all that, the effort was mostly a flop, as it failed to reach the group's older, more influential target audience. The page may have more fans than before, but money can't buy engagement; only 2 percent of the page's fans actually like or share its content.

"Many in the bureau criticize the advertising campaigns as 'buying fans' who may have once clicked on an ad or 'liked' a photo but have no real interest in the topic and have never engaged further," said the agency inspector general in a report.

My writing career has taken me all round the houses over the past decade and a half--from grumpy teens and hungover rock bands in the UK, where I was born, via celebrity interviews, health, tech and f…